Severe hyponatremia as the initial sign preceding Guillain—Barré syndrome: a case report

Abstract

Diagnosis of Guillain–Barré syndrome (GBS) is established clinically and is supported by nerve conduction studies and cerebrospinal fluid examination. Renal function is usually not affected, but recent case reports have established a link between GBS and hyponatremia. A 60-year-old woman presenting with lower back ache since 3 days, became drowsy the next day and developed paraparesis and bulbar symptoms. Her sensorium and power deteriorated progressively over the next 2 days and she was brought to hospital in a drowsy state. She was found to have severe hyponatremia (Na⁺ at 113) and nerve conduction study (NCS) was son of AMAN. The patient was started on intravenous immunoglobulin and her sodium levels were corrected, and the patient recovered completely. The occurrence of hyponatremia in patients diagnosed with GBS is well described. However, there have been only two prior case reports in which hyponatremia had been observed before the manifestation of neuromuscular deficits. Our patient case is unique in that severe hyponatremia occurred simultaneously with neurologic symptoms and the diagnosis of GBS. In most cases reported in the literature, hyponatremia was noted after a diagnosis of GBS was established. The mean period of onset of syndrome of inappropriate antidiuretic hormone (SIADH) was 8.8 days after the onset of symptoms of GBS. In conclusion, this presentation raises the possibility that early changes in the autonomic nervous system triggered by GBS might lead to alterations in water and sodium balance that can precede symptomatic changes in the peripheral nervous system. Although rarely, but both GBS and its treatment, intravenous immunoglobulin, should be considered in the differential diagnosis of hyponatremia.